Comparing post-treatment urinary and colorectal procedures in prostate cancer patients using population-based linked data.

Purpose: To investigate urinary and colorectal procedures among men who underwent radical prostatectomy (RP) and external beam radiotherapy (EBRT).

Methods: We studied 16,271 (RP = 8516 and EBRT = 7755) South Australian men diagnosed with prostate cancer between 2001 and 2021. Colorectal and urinary procedures were extracted from hospital admission procedure codes and Medical Benefits Schedule item codes. Rates were estimated at 30-days, 90-days, 6-months, 1-year, 2-years and 5-years post-treatment. We estimated the average treatment effect of RP (compared with EBRT) by applying propensity-matched analyses, accounting for sociodemographic and clinical characteristics. Subgroup analyses were undertaken for different treatment periods (2001-2010 vs. 2011-2021).

Results: At 1-year post-treatment, the crude rates of colorectal procedures were 43 and 70/1000 person-years among RP and EBRT patients, respectively, while crude rates for urinary procedures were 258 and 74/1000 person-years, respectively. Propensity matched analyses indicated that patients undergoing RP underwent more post-treatment urinary procedures, being 21.2% higher at 6-months and 16.3% higher at 5-years than men who received EBRT. Colorectal procedures were slightly more frequent among RP than EBRT patients during the first 90-days but less frequent from 1-year onwards (5.9% lower at 5-years among RP group). Between 2011 and 2021, there were considerably fewer urinary procedures for men who underwent RP than those treated between 2001 and 2010.

Conclusion: There is a statistically significant difference in the frequency of post-treatment procedures between patients who underwent RP and those who had EBRT, which likely indicates a difference in adverse treatment effects. These findings may lead to more informed treatment decision-making.